Air-cavity package with enhanced package integration level and thermal performance

ABSTRACT

The present disclosure relates to an air-cavity package, which includes a bottom substrate, a top substrate, a perimeter wall, a bottom electronic component, a top electronic component, and an external electronic component. The perimeter wall extends from a periphery of a lower side of the top substrate to a periphery of an upper side of the bottom substrate to form a cavity. The bottom electronic component is mounted on the upper side of the bottom substrate and exposed to the cavity. The top electronic component is mounted on the lower side of the top substrate and exposed to the cavity. And the external electronic component is mounted on an upper side of the top substrate, which is opposite the lower side of the top substrate and not exposed to the cavity.

RELATED APPLICATIONS

This application claims the benefit of provisional patent applicationSer. No. 62/381,703, filed Aug. 31, 2016, the disclosure of which ishereby incorporated herein by reference in its entirety.

FIELD OF THE DISCLOSURE

The present disclosure relates to an air-cavity package and a processfor making the same, and more particularly to an air-cavity package withenhanced package integration level and thermal performance, and aprocess to enhance package integration level and thermal performance ofthe air-cavity package.

BACKGROUND

In semiconductor packaging, mold compounds are normally used toencapsulate flip-chip dies and or wire-bonding dies to protect the diesagainst damage from the outside environment. However, direct contact ofthe mold compounds and active die surfaces may adversely impact itselectrical performance, especially for high frequency devices.Accordingly, it is desirable to package the dies in a configuration thatis more appropriate for high frequency performance.

Because of their promise of lower cost and better performance, highlevels of integration within semiconductor packages is highly desired.Package on package (POP), which stacks two or more semiconductorpackages vertically, is a semiconductor packaging technology that allowshigher electronics density in final products. POP offers benefits tosmall printed-circuit-board areas where short trace lengths betweendifferent semiconductor packages helps enhance device performance.However, for applications that have space constraints in the z-direction(thickness), POP may not provide an optimal package solution. Besidesspace savings considerations, the high levels of integration withinsemiconductor packages typically leads to a significant increase in thedensity of the heat flux, which increasingly requires specializedthermal management.

Accordingly, there remains a need for improved package configurations toincrease the integration level of semiconductor packages and enhance thehigh frequency performance of the semiconductor packages withoutsignificantly increasing the package size. In addition, there is also aneed to manage the increased heat generated in high performancepackages.

SUMMARY

The present disclosure relates to an air-cavity package with enhancedpackage integration level and thermal performance, and a process formaking the same. According to one embodiment, an air-cavity packageincludes a bottom substrate, a top substrate, a perimeter wall, a bottomelectronic component, a top electronic component, and an externalelectronic component. The bottom substrate includes a bottom substratebody having an upper side and a lower side and at least one bottom metalstructure on the upper side of the bottom substrate body. The topsubstrate includes a top substrate body having an upper side and a lowerside and at least one top metal structure on the lower side of the topsubstrate body. The perimeter wall extends from a periphery of the lowerside of the top substrate body to a periphery of the upper side of thebottom substrate body. As such, a cavity is defined by a portion of theupper side of the bottom substrate body, an inside surface of theperimeter wall, and a portion of the lower side of the top substratebody. The perimeter wall includes at least one signal via structure thatextends from an upper surface of the perimeter wall through theperimeter wall to a lower surface of the perimeter wall, and iselectrically coupled to the at least one bottom metal structure and theat least one top metal structure. The bottom electronic component ismounted on the upper side of the bottom substrate body and exposed tothe cavity. The top electronic component is mounted on the lower side ofthe top substrate body and exposed to the cavity. And the externalelectronic component is mounted on the upper side of the top substratebody and not within the cavity.

In one embodiment of the air-cavity package, the bottom substratefurther comprises at least one bottom thermally conductive structurethat extends from the upper side of the bottom substrate body throughthe bottom substrate body to the lower side of the bottom substratebody. The at least one bottom thermally conductive structure isthermally coupled to the bottom electronic component, and conducts heatgenerated from the bottom electronic component toward the lower side ofthe bottom substrate body.

In one embodiment of the air-cavity package, the bottom substratefurther includes a bottom signal via that extends from the upper side ofthe bottom substrate body through the bottom substrate body to the lowerside of the bottom substrate body. The bottom signal via is electricallycoupled to the at least one bottom metal structure and separated fromthe at least one bottom thermally conductive structure.

In one embodiment of the air-cavity package, the top substrate furthercomprises at least one top thermally conductive structure that extendsfrom the upper side of the top substrate body through the top substratebody to the lower side of the top substrate body. The at least one topthermally conductive structure is thermally coupled to the topelectronic component, and conducts heat generated from the topelectronic component toward the upper side of the top substrate body.

In one embodiment of the air-cavity package, the top substrate furthercomprises a top signal via extending from the upper side of the topsubstrate body through the top substrate body to the lower side of thetop substrate body. The top signal via is electrically coupled to the atleast one top metal structure and separated from the at least one topthermally conductive structure.

In one embodiment of the air-cavity package, at least one externalthermally conductive structure resides over the upper side of the topsubstrate body and is thermally coupled to the at least one topthermally conductive structure.

According to another embodiment, the air-cavity package further includesan inner wall extending from the lower side of the top substrate bodytowards the upper side of the bottom substrate body. The inner walldivides the cavity into a first cavity and a second cavity, and at leastone of the bottom electronic component and the top electronic componentis exposed to the first cavity.

According to another embodiment, the air-cavity package is included in asystem assembly. Besides the air-cavity package, the system assemblyalso includes a cold plate and a printed circuit board (PCB) with a heatsink extending through the PCB. Herein, the cold plate resides over andis thermally coupled to the at least one external thermally conductivestructure. The lower side of the bottom substrate body is over the PCBsuch that the bottom signal via is electrically coupled to the PCB andthe at least one bottom thermally conductive structure is thermallycoupled to the heat sink.

According to an exemplary process for making an air-cavity package, abottom package precursor including a bottom substrate and a bottomelectronic component is provided. The bottom substrate includes a bottomsubstrate body having an upper side and a lower side, at least onebottom metal structure on the upper side of the bottom substrate body,and at least one bottom thermally conductive structure that extends fromthe upper side of the bottom substrate body through the bottom substratebody to the lower side of the bottom substrate body. The bottomelectronic component is mounted on the upper side of the bottomsubstrate body, where the at least one bottom thermally conductivestructure is thermally coupled to the bottom electronic component andconducts heat generated from the bottom electronic component toward thelower side of the bottom substrate body. Next, a top package precursorincluding a top substrate, a top electronic component, an externalelectronic component, and at least one external thermally conductivestructure is provided. The top substrate includes a top substrate bodyhaving an upper side and a lower side, at least one top metal structureon the lower side of the top substrate body, and at least one topthermally conductive structure that extends from the upper side of thetop substrate body through the top substrate body to the lower side ofthe top substrate body. The top electronic component is mounted on thelower side of the top substrate body and thermally coupled to the atleast one top thermally conductive structure. The at least one externalthermally conductive structure is mounted on the upper side of the topsubstrate body and thermally coupled to the at least one top thermallyconductive structure. Herein, heat generated from the top electroniccomponent is conducted toward the at least one external thermallyconductive structure through the at least one top thermally conductivestructure. The external electronic component is mounted on the upperside of the top substrate body. In addition, a perimeter wall includingat least one signal via structure extending from an upper surface of theperimeter wall through the perimeter wall to a lower surface of theperimeter wall is then provided. Finally, the bottom package precursor,the perimeter wall, and the top package precursor are assembledtogether. The perimeter wall extends from a periphery of the lower sideof the top substrate body to a periphery of the upper side of the bottomsubstrate body such that a cavity is defined by a portion of the upperside of the bottom substrate body, an inside surface of the perimeterwall, and a portion of the lower side of the top substrate body. Thebottom electronic component and the top electronic component are exposedto the cavity. The external electronic component and the at least onethermally conductive structure are not within the cavity. The at leastone signal via structure is electrically coupled to the at least onebottom metal structure and the at least one top metal structure.

Those skilled in the art will appreciate the scope of the presentdisclosure and realize additional aspects thereof after reading thefollowing detailed description of the preferred embodiments inassociation with the accompanying drawing figures.

BRIEF DESCRIPTION OF THE DRAWING FIGURES

The accompanying drawing figures incorporated in and forming a part ofthis specification illustrate several aspects of the disclosure, andtogether with the description serve to explain the principles of thedisclosure.

FIGS. 1A-1B provide an exemplary air-cavity package according to oneembodiment of the present disclosure.

FIGS. 2A-2B provide an alternative air-cavity package according to oneembodiment of the present disclosure.

FIG. 3 provides an exemplary system assembly including the exemplaryair-cavity package shown in FIG. 1A.

FIG. 4 provides an exemplary system assembly including the alternativeair-cavity package shown in FIG. 2A.

FIGS. 5A-5C illustrate an exemplary process to form the exemplaryair-cavity package shown in FIG. 1A according to one embodiment of thepresent disclosure.

FIGS. 6A-6C illustrate an exemplary process to form the alternativeair-cavity package shown in FIG. 2A according to one embodiment of thepresent disclosure.

It will be understood that for clear illustrations, FIGS. 1A-6C may notbe drawn to scale.

DETAILED DESCRIPTION

The embodiments set forth below represent the necessary information toenable those skilled in the art to practice the embodiments andillustrate the best mode of practicing the embodiments. Upon reading thefollowing description in light of the accompanying drawing figures,those skilled in the art will understand the concepts of the disclosureand will recognize applications of these concepts not particularlyaddressed herein. It should be understood that these concepts andapplications fall within the scope of the disclosure and theaccompanying claims.

It will be understood that, although the terms first, second, etc. maybe used herein to describe various elements, these elements should notbe limited by these terms. These terms are only used to distinguish oneelement from another. For example, a first element could be termed asecond element, and, similarly, a second element could be termed a firstelement, without departing from the scope of the present disclosure. Asused herein, the term “and/or” includes any and all combinations of oneor more of the associated listed items.

It will be understood that when an element such as a layer, region, orsubstrate is referred to as being “on” or extending “onto” anotherelement, it can be directly on or extend directly onto the other elementor intervening elements may also be present. In contrast, when anelement is referred to as being “directly on” or extending “directlyonto” another element, there are no intervening elements present.Likewise, it will be understood that when an element such as a layer,region, or substrate is referred to as being “over” or extending “over”another element, it can be directly over or extend directly over theother element or intervening elements may also be present. In contrast,when an element is referred to as being “directly over” or extending“directly over” another element, there are no intervening elementspresent. It will also be understood that when an element is referred toas being “connected” or “coupled” to another element, it can be directlyconnected or coupled to the other element or intervening elements may bepresent. In contrast, when an element is referred to as being “directlyconnected” or “directly coupled” to another element, there are nointervening elements present.

Relative terms such as “below” or “above” or “upper” or “lower” or“horizontal” or “vertical” may be used herein to describe a relationshipof one element, layer, or region to another element, layer, or region asillustrated in the Figures. It will be understood that these terms andthose discussed above are intended to encompass different orientationsof the device in addition to the orientation depicted in the Figures.

The terminology used herein is for the purpose of describing particularembodiments only and is not intended to be limiting of the disclosure.As used herein, the singular forms “a,” “an,” and “the” are intended toinclude the plural forms as well, unless the context clearly indicatesotherwise. It will be further understood that the terms “comprises,”“comprising,” “includes,” and/or “including” when used herein specifythe presence of stated features, integers, steps, operations, elements,and/or components, but do not preclude the presence or addition of oneor more other features, integers, steps, operations, elements,components, and/or groups thereof.

Unless otherwise defined, all terms (including technical and scientificterms) used herein have the same meaning as commonly understood by oneof ordinary skill in the art to which this disclosure belongs. It willbe further understood that terms used herein should be interpreted ashaving a meaning that is consistent with their meaning in the context ofthis specification and the relevant art and will not be interpreted inan idealized or overly formal sense unless expressly so defined herein.

FIG. 1A provides an exemplary air-cavity package 10 according to oneembodiment of the present disclosure. In this embodiment, the air-cavitypackage 10 includes a bottom substrate 12, a top substrate 14, and aperimeter wall 16. In detail, the bottom substrate 12 is a multi-layersubstrate (not shown) and includes a bottom substrate body 18 having anupper side and a lower side, a first bottom metal layer 20 on the upperside of the bottom substrate body 18, a bottom slug 22, a bottom signalvia 24, and a second bottom metal layer 26 on the lower side of thebottom substrate body 18. For the purpose of this illustration, thefirst bottom metal layer 20 includes three separate metal structures: afirst metal structure 20(A), a second metal structure 20(B), and a thirdmetal structure 20(C). These metal structures 20(A)-20(C) of the firstbottom metal layer 20 may be formed as metal pads and/or traces. Thesecond bottom metal layer 26 includes two separate metal structures: afirst metal structure 26(A) and a second metal structure 26(B). Thesemetal structures 26(A) and 26(B) of the second bottom metal layer 26 maybe formed as metal pads and/or traces. In different applications, thefirst bottom metal layer 20 and the second bottom metal layer 26 mayinclude fewer or more metal structures.

The bottom slug 22 is a thermally conductive structure, which may haveat least 100 W/m·k thermal conductivity. The bottom slug 22 extends fromthe upper side of the bottom substrate body 18 through the bottomsubstrate body 18 to the lower side of the bottom substrate body 18 andis thermally coupled to the second metal structure 26B of the secondbottom metal layer 26. The bottom slug 22 may be formed from copper. Insome applications, other thermally conductive structures, such asthermal vias, may also be included in the bottom substrate 12 inaddition to or instead of the bottom slug 22. Further, the bottom signalvia 24 extends from the upper side of the bottom substrate body 18through the bottom substrate body 18 to the lower side of the bottomsubstrate body 18 and is electrically coupled to the first metalstructure 20(A) of the first bottom metal layer 20 and the first metalstructure 26(A) of the second bottom metal layer 26. In differentapplications, there may be fewer or more bottom signal vias included inthe bottom substrate 12.

The top substrate 14 is a multi-layer substrate (not shown) and includesa top substrate body 28 having an upper side and a lower side, a firsttop metal layer 30 on the upper side of the top substrate body 28, a topslug 32, a number of top thermal vias 34 (only one top thermal via islabeled with a reference number for clarity), and a second top metallayer 36 on the lower side of the top substrate body 28. The top slug 32and the top thermal vias 34 are thermally conductive structures. The topslug 32 and the top thermal vias 34 extend from the upper side of thetop substrate body 28 through the top substrate body 28 to the lowerside of the top substrate body 28. In different applications, there maybe fewer or more top slugs/top thermal vias included in the topsubstrate 14. The top slug 32 may be formed from copper and the topthermal vias 34 may be filled with epoxy or plated by copper. The firsttop metal layer 30 resides over at least a portion of the upper side ofthe top substrate body 28 and is thermally coupled to the top slug 32and the top thermal vias 34. In this embodiment, the first top metallayer 30 may be a continuous plate or sheet. For the purpose of thisillustration, the second top metal layer 36 includes three separatemetal structures: a first metal structure 36(A), a second metalstructure 36(B), and a third metal structure 36(C). These metalstructures 36(A)-36(C) of the second top metal layer 36 may be formed asmetal pads and/or traces. In different applications, the second topmetal layer 36 may include fewer or more metal structures.

The perimeter wall 16 extends from a periphery of the lower side of thetop substrate body 28 to a periphery of the upper side of the bottomsubstrate body 18. As such, a cavity 38 is defined by a portion of theupper side of the bottom substrate body 18, an inside surface of theperimeter wall 16, and a portion of the lower side of the top substratebody 28. The perimeter wall 16 includes two separate via structures: afirst signal via structure 40 and a second signal via structure 42. Thefirst signal via structure 40 extends from an upper surface of theperimeter wall 16 through the perimeter wall 16 to a lower surface ofthe perimeter wall 16, and is electrically coupled to the first metalstructure 20(A) of the first bottom metal layer 20 and the first metalstructure 36(A) of the second top metal layer 36. The second signal viastructure 42 extends from the upper surface of the perimeter wall 16through the perimeter wall 16 to the lower surface of the perimeter wall16, and is electrically coupled to the third metal structure 20(C) ofthe first bottom metal layer 20 and the third metal structure 36(C) ofthe second top metal layer 36.

In addition, the air-cavity package 10 also includes a number ofelectronic components mounted on the bottom substrate 12 and the topsubstrate 14. For the purpose of this illustration, the air-cavitypackage 10 includes a bottom wire-bonding die 44 and a bottom surfacemounted device (SMD) 46 mounted on the upper side of the bottomsubstrate body 18, and a top wire-bonding die 48 and a top SMD 50mounted on the lower side of the top substrate body 28. The bottomwire-bonding die 44, the bottom SMD 46, the top wire-bonding die 48, andthe top SMD 50 are exposed to the cavity 38. In different applications,the air-cavity package 10 may include fewer or more wire-bonding diesand SMDs.

The bottom wire-bonding die 44 includes a bottom wire-bonding die body52 mounted on the upper side of the bottom substrate body 18 via adie-attach material 54, a first bottom bonding wire 56 and a secondbottom bonding wire 58. The first bottom bonding wire 56 extends from atop surface of the bottom wire-bonding die body 52 and is electricallycoupled to the second metal structure 20(B) of the first bottom metallayer 20. The second bottom bonding wire 58 extends from the top surfaceof the bottom wire-bonding die body 52 and is electrically coupled tothe third metal structure 20(C) of the first bottom metal layer 20.Herein, the bottom slug 22 is thermally coupled to the bottomwire-bonding die 44 and conducts heat generated from the bottomwire-bonding die 44 toward the lower side of the bottom substrate body18.

The bottom SMD 46 includes a bottom SMD body 60, a first bottom SMDinterconnect 62, and a second bottom SMD interconnect 64. The firstbottom SMD interconnect 62 extends outward from a bottom surface of thebottom SMD body 60 and is coupled to the first metal structure 20(A) ofthe first bottom metal layer 20. The second bottom SMD interconnect 64extends outward from the bottom surface of the bottom SMD body 60 and iscoupled to the second metal structure 20(B) of the first bottom metallayer 20. The bottom SMD 46 may be a resistor, capacitor, inductor, orflip-chip die. If the bottom SMD 46 is a significant heat generator,there may be a thermally conductive structure (not shown) thermallycoupled to the bottom SMD 46 and conducting heat generated from thebottom SMD 46 toward the lower side of the bottom substrate body 18.

The top wire-bonding die 48 includes a top wire-bonding die body 66mounted on the lower side of the top substrate body 28 via thedie-attach material 54, a first top bonding wire 68 and a second topbonding wire 70. The first top bonding wire 68 extends from a topsurface of the top wire-bonding die body 66 and is electrically coupledto the first metal structure 36(A) of the second top metal layer 36. Thesecond top bonding wire 70 extends from the top surface of the topwire-bonding die body 66 and is electrically coupled to the second metalstructure 36(B) of the second top metal layer 36. In this embodiment,the lower side of the top substrate body 28 may not have a flat surfaceand may have a recess 72, in which the top wire-bonding die 48 ismounted. Herein, the top thermal vias 34 extend from the upper side ofthe top substrate body 28 to the recess 72, are thermally coupled to thetop wire-bonding die 48, and conduct heat generated from the topwire-bonding die 48 toward the upper side of the top substrate body 28.

The top SMD 50 includes a top SMD body 74 mounted on the lower side ofthe top substrate body 28 via a SMD-attach material 76, a first top SMDinterconnect 78, and a second top SMD interconnect 80. The first top SMDinterconnect 78 extends outward from a bottom surface of the top SMDbody 74 and is coupled to the second metal structure 36(B) of the secondtop metal layer 36. The second top SMD interconnect 80 extends outwardfrom the bottom surface of the top SMD body 74 and is coupled to thethird metal structure 36(C) of the second top metal layer 36. The topSMD 50 may be a resistor, capacitor, inductor, or flip-chip die. Herein,the top slug 32 is thermally coupled to the top SMD 50 and conducts heatgenerated from the top SMD 50 toward the upper side of the top substratebody 28.

Notice that the air-cavity package 10 has two heat dissipationinterfaces: the lower side of the bottom substrate body 18 is a firstheat dissipation interface and the upper side of the top substrate body28 is a second heat dissipation interface. The two heat dissipationinterfaces of the air-cavity package 10 may largely enhance the thermalperformance of the air-cavity package 10. The heat generated from theelectronic components mounted on the upper side of the bottom substratebody 18 (like the bottom wire-bonding die 44), may be conducted towardthe lower side of the bottom substrate body 18 through the bottomthermally conductive structures (like the bottom slug 22). The heatgenerated from the electronic components mounted on the lower side ofthe top substrate body 28 (like the top wire-bonding die 48 and the topSMD 50), may be conducted toward the upper side of the top substratebody 28 through the top thermally conductive structures (like the topslug 32 and the top thermal vias 34). Herein each thermally conductivestructure (the bottom slug 22, the top slug 32, or the top thermal vias34) is directly in a heat dissipation path and adjacent to an electriccomponent (the bottom wire-bonding die 44, the top wire-bonding die 48,or the top SMD 50).

Further, the first signal via structure 40 and the second signal viastructure 42 may be used for radio frequency (RF) signal transitionsbetween the electronic components mounted on the upper side of thebottom substrate body 18 (like the bottom wire-bonding die 44 and thebottom SMD 46) and the electronic components mounted on the lower sideof the top substrate body 28 (the top wire-bonding die 48 and the topSMD 50). Herein, the first signal via structure 40 may be electricallyisolated from the second signal via structure 42. In addition, RFsignals generated by the electronic components mounted on the lower sideof the top substrate body 28 (like the top wire-bonding die 48 and thetop SMD 50) may be transited toward the lower side of the bottomsubstrate body 18 by the first signal via structure 40 and the bottomsignal via 24. Herein, the bottom signal via 24, the first signal viastructure 40, and the second signal via structure 42 are not directly ina heat dissipation path.

The air-cavity package 10 may also include a sealing material 82 used toseal off the cavity 38. The sealing material 82 extends about anexterior portion of a top junction, which is formed between the uppersurface of the perimeter wall 16 and the lower side of the top substratebody 28, and an exterior portion of a bottom junction, which is formedbetween the lower surface of the perimeter wall 16 and the upper side ofthe bottom substrate body 18.

For some applications, as shown in FIG. 1B, the air-cavity package 10may further include an inner wall 84 to separate different electroniccomponents or provide mechanical support to the air-cavity package 10.In this embodiment, the inner wall 84 extends from the lower side of thetop substrate body 28 towards the upper side of the bottom substratebody 18 and divides the cavity 38 into a first cavity 38-1 and a secondcavity 38-2. The bottom SMD 46 and the top wire-bonding die 48 areexposed to the first cavity 38-1, and the bottom wire-bonding die 44 andthe top SMD 50 are exposed to the second cavity 38-2. The inner wall 84may include a third signal via structure 86 that extends from an uppersurface of the inner wall 84 through the inner wall 84 to a lowersurface of the inner wall 84, and is electrically coupled to the secondmetal structure 20(B) of the first bottom metal layer 20 and the secondmetal structure 36(B) of the second top metal layer 36. The third signalvia structure 86 may be used for RF signal transitions between theelectronic components mounted on the upper side of the bottom substratebody 18 (like the bottom wire-bonding die 44 and the bottom SMD 46) andthe electronic components mounted on the lower side of the top substratebody 28 (the top wire-bonding die 48 and the top SMD 50). Herein, thethird signal via structure 86 may be electrically isolated from thefirst signal via structure 40 and the second signal via structure 42.

In order to further increase the package integration level, an externalSMD 88 may be mounted on the upper side of the top substrate body 28 andnot within the cavity 38. FIG. 2A provides an alternative air-cavitypackage 10A according to one embodiment of the present disclosure. Inthis embodiment, the top substrate 14 further includes a top signal via90 extending from the upper side of the top substrate body 28 throughthe top substrate body 28 to the lower side of the top substrate body 28and coupled to the third metal structure 36(C) of the second top metallayer 36. In addition, the first top metal layer 30 is not continuous,but includes three separate metal structures: a first metal structure30(A), a second metal structure 30(B), and a third metal structure30(C). These metal structures 30(A)-30(C) of the first top metal layer30 may be formed as metal pads and/or traces. The top thermal vias 34are thermally coupled to the first metal structure 30(A) of the firsttop metal layer 30, the top slug 32 is thermally coupled to the secondmetal structure 30(B) of the first top metal layer 30, and the topsignal via 90 is electrically coupled to the third metal structure 30(C)of the first top metal layer 30.

The external SMD 88 includes an external SMD body 92, a first externalSMD interconnect 94, and a second external SMD interconnect 96. Thefirst external SMD interconnect 94 extends outward from a bottom surfaceof the external SMD body 92 and is coupled to the second metal structure30(B) of the first top metal layer 30. The second external SMDinterconnect 96 extends outward from the bottom surface of the externalSMD body 92 and is coupled to the third metal structure 30(C) of thefirst top metal layer 30. Herein, the top signal via 90 may be used forsignal transitions between the external SMD 88 and the top SMD 50.Further, RF signals generated by the external SMD 88 may be transited tothe bottom wire-bonding die 44 by the top signal via 90 and the secondsignal via structure 42. In different applications, the air-cavitypackage 10A may include multiple external SMDs mounted on the upper sideof the top substrate body 28. The external SMD 88 may be a resistor,capacitor, inductor, or flip-chip die.

The air-cavity package 10A may also include a first external thermallyconductive structure 98 and a second external thermally conductivestructure 100. The first external thermally conductive structure 98resides over the upper side of the top substrate body 28 and isthermally coupled to the top slug 32 by the second metal structure 30(B)of the first top metal layer 30. The second external thermallyconductive structure 100 resides over the upper side of the topsubstrate body 28 and is thermally coupled to the top thermal vias 34 bythe first metal structure 30(A) of the first top metal layer 30. Thefirst external thermally conductive structure 98 and the second externalthermally conductive structure 100 may be formed from copper slugs.

Further, the air-cavity package 10A may include a mold compoundcomponent 102, which resides over the upper side of the top substratebody 28 to encapsulate the external SMD 88 and sides of the firstexternal thermally conductive structure 98 and the second externalthermally conductive structure 100. An upper surface of the firstexternal thermally conductive structure 98 and an upper surface of thesecond external thermally conductive structure 100 are exposed, and maybe at a same top plane 104 as an upper surface of the mold compoundcomponent 102.

Notice that the air-cavity package 10A has two heat dissipationinterfaces: the lower side of the bottom substrate body 18 is the firstheat dissipation interface and the top plane 104 is the second heatdissipation interface. The heat generated from the electronic componentsmounted on the upper side of the bottom substrate body 18 (like thebottom wire-bonding die 44), is conducted toward the lower side of thebottom substrate body 18 through the bottom thermally conductivestructures (like the bottom slug 22). The heat generated from theelectronic components mounted on the lower side of the top substratebody 28 (like the top wire-bonding die 48 and the top SMD 50), isconducted toward the top plane 104 through the top thermally conductivestructures (like the top slug 32 and the top thermal vias 34), and theexternal thermally conductive structures (like the first externalthermally conductive structure 98 and the second external thermallyconductive structure 100).

For some applications, as shown in FIG. 2B, the air-cavity package 10Amay further include the inner wall 84 to separate different electroniccomponents or provide mechanical support to the air-cavity package 10A.In this embodiment, the inner wall 84 extends from the lower side of thetop substrate body 28 towards the upper side of the bottom substratebody 18 and divides the cavity 38 into the first cavity 38-1 and thesecond cavity 38-2. The bottom SMD 46 and the top wire-bonding die 48are exposed to the first cavity 38-1, and the bottom wire-bonding die 44and the top SMD 50 are exposed to the second cavity 38-2. The inner wall84 may include the third signal via structure 86 that extends from theupper surface of the inner wall 84 through the inner wall 84 to thelower surface of the inner wall 84, and is electrically coupled to thesecond metal structure 20(B) of the first bottom metal layer 20 and thesecond metal structure 36(B) of the second top metal layer 36. The thirdsignal via structure 86 may be used for RF signal transitions betweenthe electronic components mounted on the upper side of the bottomsubstrate body 18 (like the bottom wire-bonding die 44 and the bottomSMD 46) and the electronic components mounted on the lower side of thetop substrate body 28 (the top wire-bonding die 48 and the top SMD 50).Herein, the third signal via structure 86 may be electrically isolatedfrom the first signal via structure 40 and the second signal viastructure 42.

FIG. 3 provides an exemplary system assembly 106 including theair-cavity package 10 shown in FIG. 1A. Besides the air-cavity package10, the system assembly 106 also includes a printed circuit board (PCB)108 with a heat sink 110 extending through the PCB 108, and a cold plate112. The lower side of the bottom substrate body 18 is over the PCB 108,such that the bottom signal via 24 is electrically coupled to the PCB108 by the first metal structure 26(A) of the second bottom metal layer26. The bottom slug 22 is thermally coupled to the heat sink 110 of thePCB 108 by the second metal structure 26(B) of the second bottom metallayer 26. In addition, the cold plate 112 resides over and is thermallycoupled to the first top metal layer 30. Consequently, the heatgenerated from the electronic components mounted on the upper side ofthe bottom substrate body 18 (like the bottom wire-bonding die 44), isconducted toward the heat sink 110 of the PCB 108 through the bottomthermally conductive structures (like the bottom slug 22). The heatgenerated from the electronic components mounted on the lower side ofthe top substrate body 28 (like the top wire-bonding die 48 and the topSMD 50), is conducted to the cold plate 112 through the top thermallyconductive structures (like the top slug 32 and the top thermal vias34).

FIG. 4 provides an exemplary system assembly 106A including theair-cavity package 10A shown in FIG. 2A. Besides the air-cavity package10A, the system assembly 106A also includes the PCB 108 with the heatsink 110 extending through the PCB 108, and the cold plate 112. Thelower side of the bottom substrate body 18 is over the PCB 108, suchthat the bottom signal via 24 is electrically coupled to the PCB 108 bythe first metal structure 26(A) of the second bottom metal layer 26. Thebottom slug 22 is thermally coupled the heat sink 110 of the PCB 108 bythe second metal structure 26(B) of the second bottom metal layer 26. Inaddition, the cold plate 112 resides over and is thermally coupled tothe first external thermally conductive structure 98 and the secondexternal thermally conductive structure 100. Consequently, the heatgenerated from the electronic components mounted on the upper side ofthe bottom substrate body 18 (like the bottom wire-bonding die 44), isconducted toward the heat sink 110 of the PCB 108 through the bottomthermally conductive structures (like the bottom slug 22). The heatgenerated from the electronic components mounted on the lower side ofthe top substrate body 28 (like the top wire-bonding die 48 and the topSMD 50), is conducted to the cold plate 112 through the top thermallyconductive structures (like the top slug 32 and the top thermal vias34), and the external thermally conductive structures, (like the firstexternal thermally conductive structure 98 and the second externalthermally conductive structure 100).

FIGS. 5A-5C illustrate an exemplary process to form the exemplaryair-cavity package 10 shown in FIG. 1A. Although the exemplary processis illustrated as a series of sequential steps, the exemplary process isnot necessarily order dependent. Some operations may be done in adifferent order than that presented. Further, processes within the scopeof this disclosure may include fewer or more operations than thoseillustrated in FIGS. 5A-5C.

Initially, a bottom package precursor 114, a top package precursor 116,and the perimeter wall 16 are provided as depicted in FIG. 5A. Thebottom package precursor 114 includes the bottom substrate 12, thebottom wire-bonding die 44, and the bottom SMD 46. The configurations ofthe bottom substrate 12, the bottom wire-bonding die 44, and the bottomSMD 46 are the same as described above. As such, the bottom wire-bondingdie body 52 of the bottom wire-bonding die 44 is mounted on the upperside of the bottom substrate body 18 via the die-attach material 54. Thefirst bottom bonding wire 56 of the bottom wire-bonding die 44 iselectrically coupled to the second metal structure 20(B) of the bottomsubstrate 12. The second bottom bonding wire 58 of the bottomwire-bonding die 44 is electrically coupled to the third metal structure20(C) of the bottom substrate 12. Herein, the bottom slug 22 isthermally coupled to the bottom wire-bonding die 44, and will conductheat generated from the bottom wire-bonding die 44 toward the lower sideof the bottom substrate body 18. The bottom SMD 46 resides over theupper side of the bottom substrate body 18. The first bottom SMDinterconnect 62 of the bottom SMD 46 is coupled to the first metalstructure 20(A) of the bottom substrate 12. The second bottom SMDinterconnect 64 of the bottom SMD 46 is coupled to the second metalstructure 20(B) of the bottom substrate 12. Herein, the bottom signalvia 24 is electrically coupled to bottom SMD 46.

In addition, the top package precursor 116 includes the top substrate14, the top wire-bonding die 48, and the top SMD 50. The configurationsof the top substrate 14, the top wire-bonding die 48, and the top SMD 50are the same as described above. As such, the top wire-bonding die body66 of the top wire-bonding die 48 is mounted on the lower side of thetop substrate body 28 via the die-attach material 54. The first topbonding wire 68 of the top wire-bonding die 48 is electrically coupledto the first metal structure 36(A) of the top substrate 14. The secondtop bonding wire 70 of the top wire-bonding die 48 is electricallycoupled to the second metal structure 36(B) of the top substrate 14.Herein, the top thermal vias 34 are thermally coupled to the topwire-bonding die 48, and will conduct heat generated from the topwire-bonding die 48 toward the upper side of the top substrate body 28.The top SMD body 74 of the top SMD 50 is mounted on the lower side ofthe top substrate body 28 via the SMD-attach material 76. The first topSMD interconnect 78 of the top SMD 50 is coupled to the second metalstructure 36(B) of the top substrate 14. The second top SMD interconnect80 of the top SMD 50 is coupled to the third metal structure 36(C) ofthe top substrate 14. Herein, the top slug 32 is thermally coupled tothe top SMD 50, and will conduct heat generated from the top SMD 50toward the upper side of the top substrate body 28.

Next, the bottom package precursor 114, the top package precursor 116,and the perimeter wall 16 are assembled together as depicted in FIG. 5B.The perimeter wall 16 extends from the periphery of the lower side ofthe top substrate body 28 to the periphery of the upper side of thebottom substrate body 18 such that the cavity 38 is defined by a portionof the upper side of the bottom substrate body 18, the inside surface ofthe perimeter wall 16, and a portion of the lower side of the topsubstrate body 28. The bottom wire-bonding die 44, the bottom SMD 46,the top wire-bonding die 48, and the top SMD 50 are exposed to thecavity 38. The first signal via structure 40 of the perimeter wall 16 iselectrically coupled to the first metal structure 20(A) of the bottomsubstrate 12 and the first metal structure 36(A) of the top substrate14. The second signal via structure 42 of the perimeter wall 16 iselectrically coupled to the third metal structure 20(C) of the bottomsubstrate 12 and the third metal structure 36(C) of the top substrate14.

Finally, the sealing material 82 is applied to an exterior portion ofthe top junction, which is formed between the upper surface of theperimeter wall 16 and the lower side of the top substrate body 28, andan exterior portion of the bottom junction, which is formed between thelower surface of the perimeter wall 16 and the upper side of the bottomsubstrate body 18 as depicted in FIG. 5C. The cavity 38 is sealed off bythe sealing material 82, and the air-cavity package 10 is formed.

FIGS. 6A-6C illustrate an exemplary process to form the air-cavitypackage 10A shown in FIG. 2A. Although the exemplary process isillustrated as a series of sequential steps, the exemplary process isnot necessarily order dependent. Some operations may be done in adifferent order than that presented. Further, processes within the scopeof this disclosure may include fewer or more operations than thoseillustrated in FIGS. 6A-6C.

Initially, the bottom package precursor 114, an alternative top packageprecursor 116A, and the perimeter wall 16 are provided as depicted inFIG. 6A. The bottom package precursor 114 includes the bottom substrate12, the bottom wire-bonding die 44, and the bottom SMD 46. Theconfigurations of the bottom substrate 12, the bottom wire-bonding die44, and the bottom SMD 46 are the same as described above. As such, thebottom wire-bonding die body 52 of the bottom wire-bonding die 44 ismounted on the upper side of the bottom substrate body 18 via thedie-attach material 54. The first bottom bonding wire 56 of the bottomwire-bonding die 44 is electrically coupled to the second metalstructure 20(B) of the bottom substrate 12. The second bottom bondingwire 58 of the bottom wire-bonding die 44 is electrically coupled to thethird metal structure 20(C) of the bottom substrate 12. Herein, thebottom slug 22 is thermally coupled to the bottom wire-bonding die 44and will conduct heat generated from the bottom wire-bonding die 44toward the lower side of the bottom substrate body 18. The bottom SMD 46resides over the upper side of the bottom substrate body 18. The firstbottom SMD interconnect 62 of the bottom SMD 46 is coupled to the firstmetal structure 20(A) of the bottom substrate 12. The second bottom SMDinterconnect 64 of the bottom SMD 46 is coupled to the second metalstructure 20B of the bottom substrate 12. Herein, the bottom signal via24 is electrically coupled to bottom SMD 46.

In addition, the top package precursor 116A includes the top substrate14, the top wire-bonding die 48, the top SMD 50, the external SMD 88,the first external thermally conductive structure 98, the secondexternal thermally conductive structure 100, and the mold compoundcomponent 102. The configurations of the top substrate 14, the topwire-bonding die 48, the top SMD 50, the external SMD 88, the firstexternal thermally conductive structure 98, the second externalthermally conductive structure 100, and the mold compound component 102are the same as described above. As such, the top wire-bonding die body66 of the top wire-bonding die 48 is mounted on the lower side of thetop substrate body 28 via the die-attach material 54. The first topbonding wire 68 of the top wire-bonding die 48 is electrically coupledto the first metal structure 36(A) of the top substrate 14. The secondtop bonding wire 70 of the top wire-bonding die 48 is electricallycoupled to the second metal structure 36(B) of the top substrate 14.Herein, the top thermal vias 34 are thermally coupled to the topwire-bonding die 48. The top SMD body 74 of the top SMD 50 is mounted onthe lower side of the top substrate body 28 via the SMD-attach material76. The first top SMD interconnect 78 of the top SMD 50 is coupled tothe second metal structure 36B of the top substrate 14. The second topSMD interconnect 80 of the top SMD 50 is coupled to the third metalstructure 36C of the top substrate 14. Herein, the top slug 32 isthermally coupled to the top SMD 50 and the top signal via 90 iselectrically coupled to top SMD 50.

The external SMD 88 resides over the upper side of the top substratebody 28. The first external SMD interconnect 94 of the external SMD 88is coupled to the second metal structure 30(B) of the top substrate 14.The second external SMD interconnect 96 of the external SMD 88 iscoupled to the third metal structure 30(C) of the top substrate 14. Thefirst external thermally conductive structure 98 is thermally coupled tothe top slug 32 by the second metal structure 30(B) of the top substrate14. The second external thermally conductive structure 100 is thermallycoupled to the top thermal vias 34 by the first metal structure 30(A) ofthe top substrate 14. Further, the mold compound component 102 residesover the upper side of the top substrate body 28 to encapsulate theexternal SMD 88 and sides of the first external thermally conductivestructure 98 and the second external thermally conductive structure 100.The upper surface of the first external thermally conductive structure98 and the upper surface of the second external thermally conductivestructure 100 are exposed, and may be at the same top plane 104 as theupper surface of the mold compound component 102. Herein, the heatgenerated from the top SMD 50 is conducted toward the top plane 104through the top slug 32 and the first external thermally conductivestructure 98, and the heat generated from the top wire-bonding die 48 isconducted toward the top plane 104 through the top thermal vias 34 andthe second external thermally conductive structure 100.

Next, the bottom package precursor 114, the top package precursor 116A,and the perimeter wall 16 are assembled together as depicted in FIG. 6B.The perimeter wall 16 extends from the periphery of the lower side ofthe top substrate body 28 to the periphery of the upper side of thebottom substrate body 18 such that the cavity 38 is defined by a portionof the upper side of the bottom substrate body 18, the inside surface ofthe perimeter wall 16, and a portion of the lower side of the topsubstrate body 28. The bottom wire-bonding die 44, the bottom SMD 46,the top wire-bonding die 48, and the top SMD 50 are exposed to thecavity 38. The external SMD 88, the first external thermally conductivestructure 98, and the second external thermally conductive structure 100are not within the cavity 38. The first signal via structure 40 iselectrically coupled to the first metal structure 20(A) of the bottomsubstrate 12 and the first metal structure 36(A) of the top substrate14. The second signal via structure 42 is electrically coupled to thethird metal structure 20(C) of the bottom substrate 12 and the thirdmetal structure 36(C) of the top substrate 14.

Finally, the sealing material 82 is applied to an exterior portion ofthe top junction, which is formed between the upper surface of theperimeter wall 16 and the lower side of the top substrate body 28, andan exterior portion of the bottom junction, which is formed between thelower surface of the perimeter wall 16 and the upper side of the bottomsubstrate body 18 as depicted in FIG. 6C. The cavity 38 is sealed off bythe sealing material 82, and the air-cavity package 10A is formed.

Those skilled in the art will recognize improvements and modificationsto the preferred embodiments of the present disclosure. All suchimprovements and modifications are considered within the scope of theconcepts disclosed herein and the claims that follow.

What is claimed is:
 1. An apparatus comprising: a bottom substratecomprising a bottom substrate body having an upper side and a lower sideand at least one bottom metal structure on the upper side of the bottomsubstrate body; a top substrate comprising a top substrate body havingan upper side and a lower side and at least one top metal structure onthe lower side of the top substrate body; a perimeter wall extendingfrom a periphery of the lower side of the top substrate body to aperiphery of the upper side of the bottom substrate body such that acavity is defined by a portion of the upper side of the bottom substratebody, an inside surface of the perimeter wall, and a portion of thelower side of the top substrate body, wherein at least one signal viastructure extends from an upper surface of the perimeter wall throughthe perimeter wall to a lower surface of the perimeter wall, and iselectrically coupled to the at least one bottom metal structure and theat least one top metal structure; a bottom electronic component mountedon the upper side of the bottom substrate body and exposed to thecavity; a top electronic component mounted on the lower side of the topsubstrate body and exposed to the cavity; and an external electroniccomponent mounted on the upper side of the top substrate body and notwithin the cavity.
 2. The apparatus of claim 1 wherein the bottomsubstrate further comprises at least one bottom thermally conductivestructure that extends from the upper side of the bottom substrate bodythrough the bottom substrate body to the lower side of the bottomsubstrate body, wherein the at least one bottom thermally conductivestructure is thermally coupled to the bottom electronic component andconducts heat generated from the bottom electronic component toward thelower side of the bottom substrate body.
 3. The apparatus of claim 2further comprising a printed circuit board (PCB) with a heat sinkextending through the PCB, wherein the lower side of the bottomsubstrate body is over the PCB and the at least one bottom thermallyconductive structure is thermally coupled to the heat sink.
 4. Theapparatus of claim 2 wherein the at least one bottom thermallyconductive structure comprises a plurality of thermal vias.
 5. Theapparatus of claim 2 wherein the at least one bottom thermallyconductive structure comprises a slug.
 6. The apparatus of claim 2wherein the bottom substrate further comprises a bottom signal viaextending from the upper side of the bottom substrate body through thebottom substrate body to the lower side of the bottom substrate body,wherein the bottom signal via is electrically coupled to the at leastone bottom metal structure and separated from the at least one bottomthermally conductive structure.
 7. The apparatus of claim 6 furthercomprising a printed circuit board (PCB) with a heat sink extendingthrough the PCB, wherein: the lower side of the bottom substrate body isover the PCB such that the bottom signal via is electrically coupled tothe PCB; and the at least one bottom thermally conductive structure isthermally coupled to the heat sink.
 8. The apparatus of claim 1 whereinthe top substrate further comprises at least one top thermallyconductive structure that extends from the upper side of the topsubstrate body through the top substrate body to the lower side of thetop substrate body, wherein the at least one top thermally conductivestructure is thermally coupled to the top electronic component, andconducts heat generated from the top electronic component toward theupper side of the top substrate body.
 9. The apparatus of claim 8wherein the at least one top thermally conductive structure comprises aplurality of thermal vias.
 10. The apparatus of claim 8 wherein the atleast one top thermally conductive structure comprises a slug.
 11. Theapparatus of claim 8 wherein the top substrate further comprises a topsignal via extending from the upper side of the top substrate bodythrough the top substrate body to the lower side of the top substratebody, wherein the top signal via is electrically coupled to the at leastone top metal structure and separated from the at least one topthermally conductive structure.
 12. The apparatus of claim 8 furthercomprising at least one external thermally conductive structure thatresides over the upper side of the top substrate body and is thermallycoupled to the at least one top thermally conductive structure.
 13. Theapparatus of claim 12 further comprising a mold compound component thatresides over the upper side of the top substrate body to encapsulate theexternal electronic component and sides of the at least one externalthermally conductive structure.
 14. The apparatus of claim 12 furthercomprising a cold plate that resides over and is thermally coupled tothe at least one external thermally conductive structure.
 15. Theapparatus of claim 1 wherein the bottom electronic component is one froma group consisting of a resistor, a capacitor, an inductor, a flip-chipdie, and a wire-bonding die.
 16. The apparatus of claim 1 wherein thetop electronic component is one from a group consisting of a resistor, acapacitor, an inductor, a flip-chip die, and a wire-bonding die.
 17. Theapparatus of claim 1 wherein the external electronic component is onefrom a group consisting of a resistor, a capacitor, an inductor, and aflip-chip die.
 18. The apparatus of claim 1 further comprising: a topjunction formed between the upper surface of the perimeter wall and thelower side of the top substrate body, and a bottom junction formedbetween the lower surface of the perimeter wall and the upper side ofthe bottom substrate body; and a sealing material that extends about anexterior portion of the top junction and an exterior portion of thebottom junction to seal off the cavity.
 19. The apparatus of claim 1further comprising an inner wall extending from the lower side of thetop substrate body towards the upper side of the bottom substrate body,wherein: the inner wall divides the cavity into a first cavity and asecond cavity; and at least one of the bottom electronic component andthe top electronic component is exposed to the first cavity.
 20. Theapparatus of claim 1 wherein: the at least one signal via structurecomprises a first signal via structure and a second signal viastructure, which is separated from the first signal via structure; theat least one bottom metal structure comprises a first bottom metalstructure and a second bottom metal structure, which is separated fromthe first bottom metal structure; the at least one top metal structurecomprises a first top metal structure and a second top metal structure,which is separated from the first top metal structure; and the firstsignal via structure is electrically coupled to the first bottom metalstructure and the first top metal structure, and the second signal viastructure is electrically coupled to the second bottom metal structureand the second top metal structure.
 21. The apparatus of claim 20wherein: the bottom substrate further comprises a bottom signal viaextending from the upper side of the bottom substrate body through thebottom substrate body to the lower side of the bottom substrate body,wherein the bottom signal via is electrically coupled to the firstbottom metal structure; and the top substrate further comprises a topsignal via extending from the upper side of the top substrate bodythrough the top substrate body to the lower side of the top substratebody, wherein the top signal via is electrically coupled to the secondtop metal structure.